1. Field of the Invention
The present invention relates, generally, to apparatus for automatic handling of molded parts. More particularly, the invention relates to apparatus used on a molding machine for closing a lid on a molded part, having a base portion and a lid portion, immediately after the part is molded.
2. Background Information
The state of the art includes various devices and methods for removing molded parts from multicavity molds. When the molded part has a base portion and a hinged lid portion, sometimes it is desirable that the lid portion be closed onto the base portion before the part is processed further. Reasons for closing the hinged lid on a base immediately after molding include maintaining the sterility of the interior of a container comprising the base and the lid, folding the hinge while it is warm so it will be unstressed in a closed position, and simply to eliminate the need for that separate step later. A device that closes the lid portion of a molded part while the part is still in the mold is disclosed in U.S. Pat. Nos. 4,340,352 and 4,351,630. These patents show a separately-actuated closing mechanism that moves transverse to the mold while the mold is open. Such a mechanism is relatively complex and expensive and can add to the cycle time since it must move in, close the lid and move out of the way before the part is ejected and another molding cycle performed. Alternatively, robots are used to capture molded parts and move them out of the molding area where they are closed by a separate apparatus. Such a robot is disclosed in an article on page 170 of the May 1997 issue of Plastics Technology. Though this has minimal impact on cycle time, the robot and separate closing apparatus are separate machines in addition to the molding machine and again can be relatively complex and expensive.
A relatively simple and inexpensive mechanism for removing molded parts which does not significantly reduce molding cycle time is a mechanism that uses pivoting arms with suction devices at the end of each arm to unload molded parts as taught in U.S. Pat. Nos. 4,976,603, 5,518,387 and 5,709,833 hereby incorporated herein by reference. These patents are directed solely to part ejection and teach using a pivoting arm attached to one of the mold plates to enter an open mold space, capture an ejected molded part and transport it to a position adjacent the mold so that the part can be released.
There is a need for a simple, inexpensive mechanism to close a lid on a molded part without significantly adding to the cycle time.